Icemaker for refrigerators and control method thereof

ABSTRACT

A control method includes receiving an output value from an optical sensor to determine whether an ice bank is full of ice, driving the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice, driving the optical sensor to receive an output value from the optical sensor after lapse of the first drive time, comparing the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and driving the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation of the output value is equal to or greater than a reference variation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2011-0018957, filed on Mar. 3, 2011 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments of the present disclosure relate to a refrigerator with an icemaker operated using an improved method of sensing whether an ice bank is full of ice.

2. Description of the Related Art

A refrigerator is an apparatus that supplies cool air into a storage chamber to keep foods fresh at low temperature. The storage chamber includes a freezing chamber to keep foods at a freezing temperature or less and a refrigerating chamber to keep foods at a temperature slightly higher than the freezing temperature.

In recent years, various large-sized refrigerators have been placed on the market to provide convenience and satisfy needs for large storage space. Based on how a refrigerating chamber, freezing chamber and door(s) are disposed, such refrigerators are classified into a general refrigerator, a side-by-side refrigerator and a combination type refrigerator.

A refrigerator is provided at a door thereof with a dispenser, through which ice or water is supplied to a user. In the storage chamber is provided an icemaker to supply ice to the dispenser.

The icemaker includes an ice making unit to make ice and an ice bank to store the ice made by the ice making unit. The ice made by the ice making unit is separated from the ice making unit by an ice separator and is stored in the ice bank disposed below the ice making unit.

SUMMARY

It is an aspect of the present disclosure to provide an icemaker for refrigerators and a control method thereof that properly heat an ice-fullness sensor in a state in which an ice bank is full of ice, thereby preventing malfunction of the ice-fullness sensor due to frost and thus achieving determination as to whether the ice bank is full of ice without error.

Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure.

In accordance with one aspect of the present disclosure, a control method of an icemaker for refrigerators including an optical sensor, including a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to the intensity of light received by the light receiving part to sense whether the ice bank is full of ice and a sensor heater to heat the optical sensor so that the optical sensor is defrosted includes receiving an output value from the optical sensor to determine whether the ice bank is full of ice, driving the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice, driving the optical sensor to receive an output value from the optical sensor after lapse of the first drive time, comparing the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and driving the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation of the output value is equal to or greater than a reference variation.

The control method may further include determining that it has been normally sensed that the ice bank is full of ice and stopping the operation of the icemaker if the calculated variation of the output value is less than the reference variation.

The receiving the output value from the optical sensor to determine whether the ice bank is full of ice may include determining that the ice bank is full of ice if the received output value is equal to or less than a first reference value, determining that the ice bank is not full of ice if the received output value is equal to or greater than a second reference value, and determining that the optical sensor is frosted if the received output value is greater than the first reference value and is less than the second reference value.

The control method may further include driving the sensor heater for the second drive time to heat the optical sensor upon determining that the optical sensor is frosted and determining whether the ice bank is full of ice after lapse of the second drive time.

The control method may further include driving the sensor heater to heat the optical sensor upon determining that the optical sensor is frosted, receiving an output value from the optical sensor to determine whether the ice bank is full of ice, and further driving the sensor heater for the first drive time to heat the optical sensor upon determining that the ice bank is full of ice.

The control method may further include determining whether the ice bank is full of ice after lapse of the second drive time.

In accordance with another aspect of the present disclosure, a control method of an icemaker for refrigerators including an optical sensor, including a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to the intensity of light received by the light receiving part to sense whether the ice bank is full of ice and a sensor heater to heat the optical sensor so that the optical sensor is defrosted includes receiving an output value from the optical sensor to determine whether the ice bank is full of ice, driving the sensor heater to heat the optical sensor upon determining that the ice bank is full of ice, driving the optical sensor to receive an output value from the optical sensor, comparing the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and further driving the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation is equal to or greater than a reference variation.

The control method may further include determining whether time to drive the sensor heater has exceeded a first drive time if the calculated variation of the output value is less than the reference variation and stopping the operation of the icemaker upon determining that the time to drive the sensor heater has exceeded the first drive time.

The receiving the output value from the optical sensor to determine whether the ice bank is full of ice may include determining that the ice bank is full of ice if the received output value is equal to or less than a first reference value, determining that the ice bank is not full of ice if the received output value is equal to or greater than a second reference value, and determining that the optical sensor is frosted if the received output value is greater than the first reference value and is less than the second reference value.

The control method may further include driving the sensor heater for the second drive time to heat the optical sensor upon determining that the optical sensor is frosted and determining whether the ice bank is full of ice after lapse of the second drive time.

The control method may further include driving the sensor heater to heat the optical sensor upon determining that the optical sensor is frosted, receiving an output value from the optical sensor to determine whether the ice bank is full of ice, and further driving the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice.

The control method may further include determining whether the ice bank is full of ice after lapse of the second drive time.

In accordance with another aspect of the present disclosure, an icemaker for refrigerators includes an optical sensor, including a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to the intensity of light received by the light receiving part to sense whether the ice bank is full of ice, a sensor heater to heat the optical sensor so that the optical sensor is defrosted, and a controller to receive an output value from the optical sensor to determine whether the ice bank is full of ice, to drive the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice, to drive the optical sensor to receive an output value from the optical sensor after lapse of the first drive time, to compare the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and to drive the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation of the output value is equal to or greater than a reference variation.

In accordance with a further aspect of the present disclosure, an icemaker for refrigerators includes an optical sensor, including a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to the intensity of light received by the light receiving part to sense whether the ice bank is full of ice, a sensor heater to heat the optical sensor so that the optical sensor is defrosted, and a controller to receive an output value from the optical sensor to determine whether the ice bank is full of ice, to drive the sensor heater to heat the optical sensor upon determining that the ice bank is full of ice, to drive the optical sensor to receive an output value from the optical sensor, to compare the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and to further drive the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation is equal to or greater than a reference variation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a view showing the interior structure of a refrigerator according to an embodiment of the present disclosure in a state in which doors of the refrigerator are open;

FIG. 2 is a sectional view of the refrigerator according to the embodiment of the present disclosure;

FIG. 3 is an enlarged sectional view showing an icemaker according to an embodiment of the present disclosure;

FIG. 4 is a control block diagram of the icemaker according to the embodiment of the present disclosure;

FIG. 5 is a flow chart showing a control method of an icemaker according to an embodiment of the present disclosure; and

FIG. 6 is a flow chart showing a control method of an icemaker according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

FIG. 1 is a view showing the interior structure of a refrigerator according to an embodiment of the present disclosure in a state in which doors of the refrigerator are open, and

FIG. 2 is a sectional view of the refrigerator according to the embodiment of the present disclosure.

Referring to FIGS. 1 and 2, the refrigerator includes a main body 10 forming the external appearance thereof, vertically extending storage chambers 20 and 21 defined in the main body 10, the storage chambers 20 and 21 being open at fronts thereof, doors 35 and 36 to open and close the open fronts of the storage chambers 20 and 21, an icemaker 70 provided in one of the storage chambers 20 and 21, e.g. a freezing chamber 21, and a dispenser 37 to dispense ice from the icemaker 70 to the front of the door 36.

At the rear wall of the main body 10 is mounted an evaporator 26 to generate cool air. A machine compartment 14 is partitioned at the rear of the lower side of the main body 10. Between an inner liner 12 and an outer liner 11 of the main body is disposed a foam member 13 for thermal insulation.

Electric/electronic components, such as a compressor 15, are installed in the machine compartment 14 partitioned in the main body 10. The storage chambers 20 and 21 are located above the machine compartment 14.

Of course, a condenser (not shown), an expansion device (not shown), etc. constituting a refrigeration cycle are provided in the main body 10.

The storage chambers 20 and 21 are partitioned by a vertical partition 16. The storage chambers 20 and 21 include a refrigerating chamber 20 formed at the right side in the drawing to keep foods in a refrigerated state and a freezing chamber 21 formed at the left side of the drawing to keep foods in a frozen state.

At the rears of the storage chambers 20 and 21 is installed an inside panel 23 to partition a cool air generation chamber 27 to generate cool air to be supplied to the storage chambers 20 and 21. The evaporator 26 is installed in the cool air generation chamber 27 to generate cool air through heat exchange with ambient air.

The inside panel 23 is provided with a plurality of discharge ports 23 a formed at a predetermined interval to uniformly discharge cool air into the storage chambers 20 and 21 and a cool air channel 23 b to guide cool air to the discharge ports 23 a. Also, a circulation fan 23 c is installed at the inside panel 23 to blow heat-exchanged cool air having passed through the evaporator 26 to the cool air channel 23 b and the discharge ports 23 a.

In the storage chambers 20 and 21 are installed shelves 24 and storage boxes 25 to store foods.

A pair of doors 35 and 36 is provided to open and close the refrigerating chamber 20 and the freezing chamber 21. The doors 35 and 36 include a refrigerating chamber door 35 hingedly coupled to the main body 10 to open and close the refrigerating chamber 20 and a freezing chamber door 36 hingedly coupled to the main body 10 to open and close the freezing chamber 21.

Inside the refrigerating chamber door 35 and the freezing chamber door 36 are installed a plurality of door shelves 35 a and 36 a to store foods.

In the freezing chamber door 36 is provided a dispenser 37 to allow a user to dispense water or ice without opening the door. In the upper part of the freezing chamber 21 is provided an icemaker 70 to make and supply ice to the dispenser 37.

The icemaker 70 may include an ice making unit 100 to make ice from water supplied thereto and an ice bank 50 disposed below the ice making unit 100 to store ice separated from the ice making unit 100.

In the ice bank 50 is installed an ice feeder 53 to feed ice separated from the ice making unit 100. At the front of the ice bank 50 may be provided a crushing chamber 60 in which an ice crusher 56 to selectively crush the ice fed by the ice feeder 53 is installed.

The ice feeder 53 may include a spiral auger 55 rotated by a feeding motor 54 to feed the ice stored in the ice bank 50 to the crushing chamber 60.

The ice crusher 56 includes a stationary blade 57 and a rotary blade 58 installed at the end of the auger 55. The ice crusher 56 may produce ice cubes or crushed ice according to user selection.

The dispenser 37 is formed in a space depressed inward from the front of the freezing chamber door 36. The dispenser 37 includes a withdrawing unit 38 to withdraw an object, the withdrawing unit 38 having a withdrawing port 38 a, through which the object is withdrawn, an opening and closing member 38 b to open and close the withdrawing port 38 a, an actuating lever 39 installed at the withdrawing unit 38 to simultaneously drive the opening and closing member 38 b and the ice maker 70 provided in the freezing chamber 21, and an ice discharge channel 40 connected between the inside and outside of the freezing chamber door 36 so that the inside and outside of the freezing chamber door 36 communicate with each other to guide the ice from the icemaker 70 to the withdrawing port 38 a.

FIG. 3 is an enlarged sectional view showing an icemaker according to an embodiment of the present disclosure.

At the lower side of the ice making unit 100 may be provided an ice-fullness sensor 80 to sense whether the ice bank 50 is full of ice. An optical sensor including a light emitting part to irradiate infrared light and a light receiving part to receive the infrared light irradiated from the light emitting part and to generate an electric signal may be used as the ice-fullness sensor 80. Hereinafter, an optical sensor will be described as an example of the ice-fullness sensor 80.

A light emitting part to irradiate infrared light may be provided at the rear of the lower side of the ice making unit 100. A light receiving part may be provided at the front of the lower side of the ice making unit 100 so that the light receiving part faces the light emitting part. Infrared light is irradiated from the light emitting part, passes through a space of the ice bank 50, in which ice is stored, and is received by the light receiving part.

The above-mentioned positions of the ice-fullness sensor 80 are defined merely as an example. The ice-fullness sensor 80 may be installed at any position as long as the light emitting part and the light receiving part face each other to sense whether the ice bank 50 is full of ice.

Sensor heaters 110 to remove frost from the light emitting part and the light receiving part of the ice-fullness sensor 80 may be provided at the lower sides of the light emitting part and the light receiving part. The intensity of infrared light irradiated by the light emitting part or received by the light receiving part when frost is formed at the ice-fullness sensor 80 may be different from that of infrared light irradiated by the light emitting part or received by the light receiving part when no frost is formed at the ice-fullness sensor 80, and therefore, it may not be normally sensed whether the ice bank 50 is full of ice.

The sensor heaters 110 remove frost from the ice-fullness sensor 80 so that the ice-fullness sensor 80 normally senses whether the ice bank 50 is full of ice. In the drawing, the sensor heaters 110 are provided at the lower side of the ice-fullness sensor 80 in contact with the ice-fullness sensor 80. However, the sensor heaters 110 may be installed at any position as long as the sensor heaters 110 removes frost from the ice-fullness sensor 80.

FIG. 4 is a control block diagram of the icemaker according to the embodiment of the present disclosure.

The icemaker 70 includes an actuating lever 39 installed at the withdrawing part 38 to actuate the icemaker 70, an ice-fullness sensor 80 to sense whether the ice bank 50 is full of ice, a controller 90 to generate a control signal according to signals input from the actuating lever 39 and the ice-fullness sensor 80 to control a drive part 120, an ice making unit 100 to make ice according to the control signal from the controller 90, sensor heaters 110 to heat the ice-fullness sensor 80 to remove frost from the ice-fullness sensor 80, a water supply device 18 to supply water to the ice making unit 100, and a drive unit 120 to drive a feeding motor 54 to feed ice stored in the ice bank 50 to the crushing chamber 60.

The actuating lever 39 is installed at the withdrawing part 38 to simultaneously drive the opening and closing member 38 b to open and close the withdrawing port 38 a and the ice maker 70 provided in the freezing chamber 21.

The ice-fullness sensor 80 includes a light emitting part to irradiate infrared light and a light receiving part to receive the infrared light irradiated from the light emitting part. Upon receiving the infrared light irradiated from the light emitting part, the light receiving part transmits intensity of the light or whether the light has been received to the controller 90 as an electric signal. The controller 90 analyzes the electric signal transmitted from the ice-fullness sensor 80 to determine a state of the ice bank 50.

If the ice bank 50 is full of ice, the ice is also located on an infrared irradiation route, and therefore, the ice obstructs or blocks advance of the infrared light irradiated from the light emitting part. As a result, intensity of the infrared light reaching the light receiving part is changed. If the ice-fullness sensor 80 converts the changed intensity of the infrared light into an electric signal and transmits the electric signal to the controller 90, the controller 90 determines that the ice bank 50 is full of ice and stops the operation of the ice making unit 100.

The ice making unit 100 stores the water supplied from the water supply device 18 and makes ice using supplied cool air. The ice made by the ice making unit 100 is moved to the ice bank 50, in which the ice is accumulated. The above process is repeated until the ice bank 50 is full of ice.

The sensor heaters 110 are provided adjacent to the light emitting part and the light receiving part constituting the ice-fullness sensor 80 to heat the light emitting part and the light receiving part. If the light emitting part, which irradiates infrared light, and the light receiving part, which receives the infrared light irradiated from the light emitting part, are frosted, ice-fullness sensing is not normally performed. For this reason, the sensor heaters 110 heat the light emitting part and the light receiving part to defrost the light emitting part and the light receiving part.

After the lapse of an ice making time, the controller 90 drives the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice. The controller 90 may store first and second reference values, based on which the controller 90 determines a state of the ice bank 50 according to the intensity of a signal transmitted from the ice-fullness sensor 80. The first reference value is a reference value to determine whether the ice bank 50 is full of ice. The second reference value is a reference value to determine whether the ice-fullness sensor 80 is frosted upon determining that the ice bank 50 is not full of ice. For example, if a voltage value of the signal transmitted from the ice-fullness sensor 80 is 1 V (first reference value) or less, the controller 90 determines that the ice bank 50 is full of ice. If the voltage value of the signal transmitted from the ice-fullness sensor 80 exceeds 1 V, the controller 90 determines that the ice bank 50 is not full of ice. In a case in which it is determined that the ice bank 50 is not full of ice, if the voltage value of the signal transmitted from the ice-fullness sensor 80 is 2.5 V or more, the controller 90 determines that the ice bank 50 is not full of ice. If the voltage value of the signal transmitted from the ice-fullness sensor 80 is 1 to 2.5 V, the controller 90 determines that the ice-fullness sensor 80 is frosted. The above reference values are given as an example. Other optimal values obtained through repeated experimentation may be applied.

Upon determining that the ice bank 50 is not full of ice, the controller 90 continuously drives the ice making unit 100 to complete the ice making process. The ice making process includes water supply, ice production and ice separation.

The controller 90 may store information on time to additionally drive the ice making unit 100 so that the ice making unit 100 is continuously driven upon determining that the ice bank 50 is not full of ice. When the additional drive time elapses, therefore, the controller 90 determines whether the ice bank 50 is full of ice.

Upon determining that the light emitting part and the light receiving part of the ice-fullness sensor 80 are frosted, the controller 90 drives the sensor heaters 110 for a predetermined time (hereinafter, referred to as a second drive time) to defrost the ice-fullness sensor 80. After the lapse of the second drive time, the controller 90 stops the operation of the sensor heaters 110 and determines whether the ice bank 50 is full of ice.

Upon determining that the ice bank 50 is full of ice, the controller 90 drives the sensor heaters 110 for a predetermined time (hereinafter, referred to as a first drive time). If the ice-fullness sensor 80 has been excessively frosted although the ice bank 50 is not full of ice, and therefore, a signal generated by the ice-fullness sensor 80 has an intensity approximate to that of a signal in a state in which the ice bank 50 is full of ice, the controller 90 may incorrectly determine that the ice bank 50 is full of ice. Even in a case in which it is determined that the ice bank 50 is full of ice, therefore, the operation of the ice making unit 100 is not stopped, and the sensor heaters 110 are driven to defrost the ice-fullness sensor 80.

The first drive time is a time to drive the sensor heaters 110 in a case in which it is incorrectly determined that the ice bank 50 is full of ice. The second drive time is a time to drive the sensor heaters 110 so that the ice-fullness sensor 80 is defrosted when it is determined that the ice-fullness sensor 80 is frosted. Therefore, the second drive time may be longer than the first drive time.

If the time to drive the sensor heaters 110 exceeds the first drive time, the controller 90 stops the operation of the sensor heaters 110 and drives the ice-fullness sensor 80 to sense a state of the ice bank 50.

The controller 90 compares a voltage value of a signal when a state of the ice bank 50 is sensed after the lapse of the first drive time with that of a sensed signal when it is determined that the ice bank 50 is full of ice to calculate variation.

If the calculated voltage variation is equal to or greater than a reference variation, the controller 90 determines that the ice-fullness sensor 80 has incorrectly sensed that the ice bank 50 is full of ice and determines that the ice-fullness sensor 80 is frosted. If the calculated voltage variation is less than the reference variation, the controller 90 determines that the ice-fullness sensor 80 has correctly sensed that the ice bank 50 is full of ice and stops the operation of the ice making unit 100.

For example, if a voltage value of a signal sensed by the ice-fullness sensor 80 is 0.9 V, which is less than the first reference value, 1 V, with the result that the ice bank 50 is full of ice, a voltage value of a sensed signal when a state of the ice bank 50 is sensed after the sensor heaters 110 are driven for the first drive time, 1 minute, is 1.3 V, and variation is 0.4 V, which is greater than the reference variation, 0.3 V, the controller determines that the ice bank 50 is not full of ice but the ice-fullness sensor 80 is frosted. The above first reference value, first drive time and reference variation are given as an example. Other optimal values obtained through repeated experimentation may be applied.

Upon determining that the ice bank 50 is not full of ice but the ice-fullness sensor 80 is frosted, the controller 110 drives the sensor heaters 110 for the second drive time to defrost the ice-fullness sensor 80.

After the lapse of the second drive time, the controller 90 determines whether the ice bank 50 is full of ice.

The above algorithm prevents the operation of the ice making unit 100 from being stopped in a case in which it is incorrectly determined that the ice-fullness sensor 80 is frosted and thus the ice bank 50 is full of ice.

FIG. 5 is a flow chart showing a control method of an icemaker according to an embodiment of the present disclosure.

As shown in FIG. 5, the controller 90 drives the ice-fullness sensor 80 and receives a value output from the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice (200). As previously described, an optical sensor including a light emitting part to irradiate infrared light and a light receiving part to receive the infrared light irradiated from the light emitting part may be used as the ice-fullness sensor 80. When infrared light is irradiated from the light emitting part, the light receiving part receives the infrared light irradiated from the light emitting part, converts the intensity of the infrared light varying based on a state of the ice bank 50, and transmits the signal to the controller 90.

The controller 90 compares the output value transmitted from the ice-fullness sensor 80 with the first reference value to determine whether the ice bank 50 is full of ice (210). If a voltage value of the signal transmitted from the ice-fullness sensor 80 is equal to or less than the first reference value, the controller 90 determines that the ice bank 50 is full of ice.

If the voltage value of the signal transmitted from the ice-fullness sensor 80 exceeds the first reference value, the controller 90 compares the voltage value with the second reference value to determine a state of the ice bank 50 (220).

If the voltage value of the signal transmitted from the ice-fullness sensor 80 is equal to or less than the second reference value, the controller 90 determines that the ice bank 50 is not full of ice and controls the ice making unit 100 to continuously perform the ice making process including water supply, ice production and ice separation (230).

The controller 90 may store information on time to additionally drive the ice making unit 100 so that the ice making unit 100 is continuously driven upon determining that the ice bank 50 is not full of ice. When the additional drive time elapses, the controller 90 drives the ice-fullness sensor 80 and receives a value output from the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice.

If the voltage value of the signal transmitted from the ice-fullness sensor 80 is less than the second reference value, the controller 90 determines that the light emitting part and the light receiving part of the ice-fullness sensor 80 are frosted and drives the sensor heaters 110 for the second drive time to defrost the ice-fullness sensor 80 (240). When the second drive time elapses, the controller 90 stops the operation of the sensor heaters 110, drives the ice-fullness sensor 80, and receives a value output from the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice.

Upon determining that the ice bank 50 is full of ice, the controller 90 drives the sensor heaters 110 for the first drive time to heat the ice-fullness sensor 80 (250). If the ice-fullness sensor 80 has become excessively frosted, it may be incorrectly determined that the ice bank 50 is full of ice. Even in a case in which it is determined that the ice bank 50 is full of ice, therefore, the operation of the ice making unit 100 is not stopped, and the sensor heaters 110 are driven to defrost the ice-fullness sensor 80. The second drive time to drive the sensor heaters 110 may be longer than the first drive time.

If the time to drive the sensor heaters 110 exceeds the first drive time, the controller 90 stops the operation of the sensor heaters 110, drives the ice-fullness sensor 80, and receives a value output from the ice-fullness sensor 80 to sense a state of the ice bank 50 (260).

The controller 90 compares an output value of a signal generated when the ice-fullness sensor 80 senses a state of the ice bank 50 with that of a signal when it is determined that the ice bank 50 is full of ice to calculate variation, and compares the calculated variation of the output value with a predetermined reference variation (270).

If the calculated variation of the output value is equal to or greater than the reference variation, the controller 90 determines that the ice-fullness sensor 80 has incorrectly sensed that the ice bank 50 is full of ice and determines that the ice-fullness sensor 80 is frosted. The process returns to Operation 240 to defrost the ice-fullness sensor 80.

If the calculated variation of the output value is less than the reference variation, the controller 90 determines that the ice-fullness sensor 80 has correctly sensed that the ice bank 50 is full of ice and stops the operation of the ice making unit 100 (280).

FIG. 6 is a flow chart showing a control method of an icemaker according to another embodiment of the present disclosure

As shown in FIG. 6, the controller 90 drives the ice-fullness sensor 80 and receives a value output from the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice (300). As previously described, an optical sensor including a light emitting part to irradiate infrared light and a light receiving part to receive the infrared light irradiated from the light emitting part may be used as the ice-fullness sensor 80.

The controller 90 compares the output value transmitted from the ice-fullness sensor 80 with the first reference value to determine whether the ice bank 50 is full of ice (310). If a voltage value of the signal transmitted from the ice-fullness sensor 80 is equal to or less than the first reference value, the controller 90 determines that the ice bank 50 is full of ice.

If the voltage value of the signal transmitted from the ice-fullness sensor 80 exceeds the first reference value, the controller 90 compares the voltage value with the second reference value to determine a state of the ice bank 50 (320).

If the voltage value of the signal transmitted from the ice-fullness sensor 80 is equal to or less than the second reference value, the controller 90 determines that the ice bank 50 is not full of ice and controls the ice making unit 100 to continuously perform the ice making process including water supply, ice production and ice separation (330).

The controller 90 may store information on time to additionally drive the ice making unit 100 so that the ice making unit 100 is continuously driven upon determining that the ice bank 50 is not full of ice. When the additional drive time elapses, the controller 90 drives the ice-fullness sensor 80 and receives a value output from the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice.

If the voltage value of the signal transmitted from the ice-fullness sensor 80 is less than the second reference value, the controller 90 determines that the light emitting part and the light receiving part of the ice-fullness sensor 80 are frosted and drives the sensor heaters 110 for the second drive time to defrost the ice-fullness sensor 80 (340). When the second drive time elapses, the controller 90 stops the operation of the sensor heaters 110, drives the ice-fullness sensor 80, and receives a value output from the ice-fullness sensor 80 to determine whether the ice bank 50 is full of ice.

Upon determining that the ice bank 50 is full of ice, the controller 90 drives the sensor heaters 110 to heat the ice-fullness sensor 80 (350).

When the operation of the sensor heaters 110 is commenced, the controller 90 drives the ice-fullness sensor 80 and receives a value output from the ice-fullness sensor 80 to sense a state of the ice bank 50 (360).

In the embodiment shown in FIG. 5, the ice-fullness sensor 80 is driven to sense a state of the ice bank 50 upon completing the operation of the sensor heaters 110 for the first drive time. In the embodiment shown in FIG. 6, on the other hand, the ice bank 50 is continuously sensed during the operation of the sensor heaters 110.

The controller 90 continuously compares an output value of a signal generated when the ice-fullness sensor 80 senses a state of the ice bank 50 during the operation of the sensor heaters 110 with that of a signal upon determining that the ice bank 50 is full of ice to calculate variation of the output value, and continuously compares the variation of the output value with a predetermined reference variation (370).

If the calculated variation of the output value is equal to or greater than the reference variation, the controller 90 determines that the ice-fullness sensor 80 has incorrectly sensed that the ice bank 50 is full of ice and determines that the ice-fullness sensor 80 is frosted. The process returns to Operation 340. That is, upon determining that the variation of the output value is equal to or greater than the reference variation, the sensor heaters 110 are additionally driven for the second drive time to defrost the ice-fullness sensor 80.

Operation 340 may be changed based on the algorithm used in Operation 360. That is, determining that the light emitting part and the light receiving part constituting the ice-fullness sensor 80 are frosted (including both advances from Operation 310 to Operation 340 and from Operation 370 to Operation 340), the controller 90 drives the sensor heaters 110 to defrost the ice-fullness sensor 80.

When the operation of the sensor heaters 110 is commenced, the controller 90 drives the ice-fullness sensor 80 to continuously determine whether the ice bank 50 is full of ice during the operation of the sensor heaters 110.

Upon determining that the ice bank 50 is full of ice or that the ice bank 50 is not full of ice, the controller 90 stops operation of the sensor heaters 110 even in a case in which the time to drive the sensor heaters 110 has not exceeded the second drive time, and perform the next control operation.

For example, if a voltage value of a signal transmitted from the ice-fullness sensor 80 is 1.5 V, which is between the first reference value, 1 V, and the second reference value, 2.5 V, and therefore, upon determining that the ice-fullness sensor 80 is frosted, the controller 90 drives the sensor heaters 110 and the ice-fullness sensor 80 and receives a value output from the ice-fullness sensor 80 to continuously sense and determine a state of the ice bank 50. If the output value of the signal increases to 2.5 V or more, the controller 90 stops the operation of the sensor heaters 110, even in a case in which the time to drive the sensor heaters 110 has not exceeded the second drive time, determines that the ice bank 50 is not full of ice, and perform the ice making process. If the output value of the signal decreases to 1 V or less, the controller 90 stops the operation of the sensor heaters 110, even in a case in which the time to drive the sensor heaters 110 has not exceeded the second drive time, determines that the ice bank 50 is full of ice, and performs the subsequent control process.

At Operation 370, if the variation of the output value, calculated through continuous comparison of the output value of the signal generated when the ice-fullness sensor 80 senses a state of the ice bank 50 during the operation of the sensor heaters 110 with that of a signal when it is determined that the ice bank 50 is full of ice, is less than the reference variation, the controller 90 determines whether time to drive the sensor heaters 110 has exceeded the first drive time (380).

The variation of the output value is less than the reference variation. As the ice-fullness sensor 80 is continuously heated, however, the variation of the output value may exceed the reference variation. If the variation of the output value is less than the reference variation, therefore, the operation of the icemaker is not immediately stopped, and it is determined whether time to drive the sensor heaters has exceeded the first drive time.

If the variation of the output value is less than the reference variation, and the time to drive the sensor heaters has exceeded the first drive time, the controller 90 determines that the ice-fullness sensor 80 has correctly sensed that the ice bank 50 is full of ice and stops the operation of the ice making unit 100 (390). Stopping the operation of the ice making unit 100 includes stopping the operations of the sensor heaters 110 and the ice-fullness sensor 80.

As is apparent from the above description, incorrect sensing of the ice-fullness sensor due to frost is prevented when it is determined whether the ice bank is full of ice, thereby achieving more correct determination as to whether the ice bank is full of ice.

Also, the sensor heaters are properly driven according to a state of the ice bank, thereby reducing energy loss due to excessive operation of the sensor heaters.

Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A control method of an icemaker for refrigerators comprising an optical sensor, comprising a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to an intensity of light received by the light receiving part to sense whether the ice bank is full of ice and a sensor heater to heat the optical sensor so that the optical sensor is defrosted, the control method comprising: receiving an output value from the optical sensor to determine whether the ice bank is full of ice; driving the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice; driving the optical sensor to receive an output value from the optical sensor after lapse of the first drive time; comparing the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value; and driving the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation of the output value is equal to or greater than a reference variation.
 2. The control method according to claim 1, further comprising determining that it has been normally sensed that the ice bank is full of ice and stopping an operation of the icemaker if the calculated variation of the output value is less than the reference variation.
 3. The control method according to claim 1, wherein the receiving the output value from the optical sensor to determine whether the ice bank is full of ice comprises: determining that the ice bank is full of ice if the received output value is equal to or less than a first reference value; determining that the ice bank is not full of ice if the received output value is equal to or greater than a second reference value; and determining that the optical sensor is frosted if the received output value is greater than the first reference value and is less than the second reference value.
 4. The control method according to claim 3, further comprising: driving the sensor heater for the second drive time to heat the optical sensor upon determining that the optical sensor is frosted; and determining whether the ice bank is full of ice after lapse of the second drive time.
 5. The control method according to claim 3, further comprising: driving the sensor heater to heat the optical sensor upon determining that the optical sensor is frosted; receiving an output value from the optical sensor to determine whether the ice bank is full of ice; and further driving the sensor heater for the first drive time to heat the optical sensor upon determining that the ice bank is full of ice.
 6. The control method according to claim 1, further comprising determining whether the ice bank is full of ice after lapse of the second drive time.
 7. A control method of an icemaker for refrigerators comprising an optical sensor, comprising a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to an intensity of light received by the light receiving part to sense whether the ice bank is full of ice and a sensor heater to heat the optical sensor so that the optical sensor is defrosted, the control method comprising: receiving an output value from the optical sensor to determine whether the ice bank is full of ice; driving the sensor heater to heat the optical sensor upon determining that the ice bank is full of ice; driving the optical sensor to receive an output value from the optical sensor; comparing the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value; and further driving the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation is equal to or greater than a reference variation.
 8. The control method according to claim 7, further comprising: determining whether time to drive the sensor heater has exceeded a first drive time if the calculated variation of the output value is less than the reference variation; and stopping an operation of the icemaker upon determining that the time to drive the sensor heater has exceeded the first drive time.
 9. The control method according to claim 7, wherein the receiving the output value from the optical sensor to determine whether the ice bank is full of ice comprises: determining that the ice bank is full of ice if the received output value is equal to or less than a first reference value; determining that the ice bank is not full of ice if the received output value is equal to or greater than a second reference value; and determining that the optical sensor is frosted if the received output value is greater than the first reference value and is less than the second reference value.
 10. The control method according to claim 9, further comprising: driving the sensor heater for the second drive time to heat the optical sensor upon determining that the optical sensor is frosted; and determining whether the ice bank is full of ice after lapse of the second drive time.
 11. The control method according to claim 9, further comprising: driving the sensor heater to heat the optical sensor upon determining that the optical sensor is frosted; receiving an output value from the optical sensor to determine whether the ice bank is full of ice; and further driving the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice.
 12. The control method according to claim 9, further comprising determining whether the ice bank is full of ice after lapse of the second drive time.
 13. An icemaker for refrigerators, comprising: an optical sensor, comprising a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to an intensity of light received by the light receiving part to sense whether the ice bank is full of ice; a sensor heater to heat the optical sensor so that the optical sensor is defrosted; and a controller to receive an output value from the optical sensor to determine whether the ice bank is full of ice, to drive the sensor heater for a first drive time to heat the optical sensor upon determining that the ice bank is full of ice, to drive the optical sensor to receive an output value from the optical sensor after lapse of the first drive time, to compare the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and to drive the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation of the output value is equal to or greater than a reference variation.
 14. An icemaker for refrigerators, comprising: an optical sensor, comprising a light emitting part and a light receiving part to receive light irradiated from the light emitting part and transmitted through an internal space of an ice bank to store ice, to output a signal according to an intensity of light received by the light receiving part to sense whether the ice bank is full of ice; a sensor heater to heat the optical sensor so that the optical sensor is defrosted; and a controller to receive an output value from the optical sensor to determine whether the ice bank is full of ice, to drive the sensor heater to heat the optical sensor upon determining that the ice bank is full of ice, to drive the optical sensor to receive an output value from the optical sensor, to compare the output value with the output value received to determine whether the ice bank is full of ice to calculate variation of the output value, and to further drive the sensor heater for a second drive time to heat the optical sensor so that the optical sensor is defrosted if the calculated variation is equal to or greater than a reference variation.
 15. The ice maker according to claim 14, further comprising an ice making unit to make ice from water supplied thereto, wherein the ice bank disposed below the ice making unit and stores ice separated from the ice making unit.
 16. The ice maker according to claim 15, further comprising: an ice feeder installed in the ice bank to feed ice separated from the ice making unit; a crushing chamber installed at the front of the ice bank, the crushing chamber including an ice crusher to selectively crush the ice fed by the ice feeder.
 17. The ice maker according to claim 16, wherein the ice feeder includes a spiral auger rotated by a feeding motor to feed the ice stored in the ice bank to the crushing chamber.
 18. The ice maker according to claim 17, wherein the ice crusher includes a stationary blade and a rotary blade installed at the end of the auger. 